20 Gy Gamma Knife Radiosurgery For Brain Metastases = 2 Cm In Size In Or Near Eloquent Cortices: Symptom Resolution And Risk Of New Deficits

Keywords: gamma knife, radiosurgery, brain metastasis, outcome, cortex

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     Reports of surgical resection of tumors in or near eloquent cortices have noted neurological complications in up to 30% of patients.
     We sought to analyze symptom resolution and neurological morbidity of 20 Gy gamma knife radiosurgery (GKR) for supratentorial brain metastases, 2 cm in greatest diameter.
     A retrospective analysis of 101 consecutive adults (32 males/69 females/median age 62 years) with KPS,60 who received GKR for supratentorial brain metastases, 2 cm in size was performed. 
     Lesion location was classified as eloquent, near eloquent or noneloquent as per the grading system by Sawaya (1998). Following treatment, patients underwent MRI and clinical examinations at 6 weeks and every 3 months thereafter. Four patients with 7 treated lesions who expired before 3 months following GKR were excluded to reduce underestimation of new deficits.
     Ninety-seven patients underwent 20 Gy GKR of 130 metastases at initial presentation and 31 patients had salvage 20 Gy GKR of 76 new lesions (mean/median volume: 0.29/0.19 cc). Lesions were classified as follows: eloquent—60 (29.1%), near eloquent—49 (23.8%) and noneloquent—97 (47.1%). The most common eloquent locations were precentral gyrus (21 35.6%), postcentral gyrus (15 25.4%) and calcarine (14 23.7%). Twelve patients (10-eloquent/2-near eloquent) had deficits referable to their treated lesions yielding a pre-GKR deficit rate of 5.8% per lesion and 12.4% per patient. Pre-GKR deficits improved in 7 patients (58%) at a median time of 3 months. One patient developed a new hemiparesis and 4 had worsening of pre-GKR deficits at a median of 3 months. New deficits resolved in 2 of these patients. The rates of permanent neurological deficits for lesions in or near eloquent cortices were 3.3% (2/60) and 2% (1/50), respectively. The rate of new or worsening of hemiparesis for perirolandic lesions was 5.7% (2/35). No patients with lesions in noneloquent locations had deficits prior to or following GKR.
     This is a retrospective study.
     GKR with 20 Gy provides palliation of neurological deficits from brain metastases £ 2 cm in or near eloquent cortices with low morbidity.
     Consistent with surgical literature, higher rates of neurological complications were seen as proximity to eloquent regions increased.


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